In the display as described above, it is required that the image display surface of the display is imparted with hardness to avoid being scratched upon handling. To meet the request, in general, an optical film comprising a hard coat (HC) layer provided on a substrate film is used to impart hardness to the image display surface of the display (Patent Literature 1).
As shown in FIG. 1, a general touch panel comprises, for example, two optically-transparent substrates 10 and 11 each provided with Indium Tin Oxide (ITO) being transparent electroconductive films 20 and 21 (hereinafter, transparent electroconductive film 21 on a display side may be referred to as “second transparent electroconductive film” to be distinguished from transparent electroconductive film 20), which are disposed so that transparent electroconductive films 20 and 21 are faced each other via spacers 30. On the input operation side-surface of optically-transparent substrate 10, hard coat layer 40 for imparting hardness and abrasion resistance is provided. Display 80 is disposed on the surface side of optically-transparent substrate 11, which is opposite to the surface side where transparent electroconductive film 21 is present. Then, hard coat layer 40, optically-transparent substrate 10 and transparent electroconductive film 20, which are located closer to the input operation side than spacers 30 of touch panel 150, are pressed with a finger, stylus pen 70 or the like to input information, and the pressed part of input operation side-transparent electroconductive film 20 is brought into contact with display 80 side-second transparent electroconductive film 21. Thus, positional information is detected.
At this time, in the part where the transparent electroconductive films are contacted by the input operation and the vicinity thereof, light reflected from surface 50 on the display side of transparent electroconductive film 20 interferes with light reflected from surface 60 on the input operation side of second transparent electroconductive film 21. Therefore, there has been a problem that interference fringes called “Newton ring” occur, thus, visibility of the display decreases.
In response to the above problem, in Patent Literature 2, there has been proposed a touch panel comprising one or both of electroconductive films on an anti-Newton ring layer having an arithmetic mean roughness (Ra) of 0.07 to 0.3 μm and maximum height (Ry) of 1.5 to 2.0 μm in order to prevent Newton ring formation.
However, there has been a problem that the touch panel having a large Ra as proposed in Patent Literature 2 has glare when disposed on the front surface (input operation side) of the display, and visibility decreases due to the glare.